In a projection system, an image-bearing light beam is generated from a light engine and ultimately cast onto a viewing surface. Light engines commonly include a light source, a means for generating color (e.g., a color wheel), and a light modulator, which modulates the light beam before projecting a resultant image onto the viewing surface. To generate a light beam, a light source typically includes a mercury lamp or a plurality of light emitting diodes (LEDs). Although mercury lamps have long been a reliable light source, their size and inability to produce adequate light in the upper wavelengths of the visible range make them less suitable for modern projection systems. LEDs, on the other hand, provide a reliable and less expensive alternative to using mercury lamps. The problem, however, is that LEDs generally produce unfocused and undirected light that is difficult to converge and direct.
In addition, light sources generally require a color wheel, or other subtractive color device, wherein colored light is produced by filtering white light. With respect to color wheels in particular, there are also moving parts, which are disadvantageous from a maintenance standpoint.
The embodiments described hereinafter were developed in light of these and other drawbacks associated with known light source configurations.